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Fix GH-19790: integer overflowq in imagerectangle #19791

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Fix GH-19790: integer overflowq in imagerectangle #19791

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26 changes: 21 additions & 5 deletions ext/gd/libgd/gd.c
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Original file line number Diff line number Diff line change
Expand Up @@ -712,13 +712,17 @@ void gdImagePaletteCopy (gdImagePtr to, gdImagePtr from)
*/

static int clip_1d(int *x0, int *y0, int *x1, int *y1, int maxdim) {
double m; /* gradient of line */
double m, tmp; /* gradient of line */

if (*x0 < 0) { /* start of line is left of window */
if(*x1 < 0) { /* as is the end, so the line never cuts the window */
return 0;
}
m = (*y1 - *y0)/(double)(*x1 - *x0); /* calculate the slope of the line */
tmp = (double)*x1 - (double)*x0;
if (tmp < (double)INT_MIN || tmp == 0.0 || tmp > (double)INT_MAX) {
return 0;
}
m = (*y1 - *y0)/tmp; /* calculate the slope of the line */
/* adjust x0 to be on the left boundary (ie to be zero), and y0 to match */
*y0 -= (int)(m * *x0);
*x0 = 0;
Expand All @@ -733,7 +737,11 @@ static int clip_1d(int *x0, int *y0, int *x1, int *y1, int maxdim) {
if (*x1 > maxdim) { /* as is the end, so the line misses the window */
return 0;
}
m = (*y1 - *y0)/(double)(*x1 - *x0); /* calculate the slope of the line */
tmp = (double)*x1 - (double)*x0;
if (tmp < (double)INT_MIN || tmp == 0.0 || tmp > (double)INT_MAX) {
return 0;
}
m = (*y1 - *y0)/tmp; /* calculate the slope of the line */
*y0 += (int)(m * (maxdim - *x0)); /* adjust so point is on the right boundary */
*x0 = maxdim;
/* now, perhaps, adjust the end of the line */
Expand All @@ -745,13 +753,21 @@ static int clip_1d(int *x0, int *y0, int *x1, int *y1, int maxdim) {
}
/* the final case - the start of the line is inside the window */
if (*x1 > maxdim) { /* other end is outside to the right */
m = (*y1 - *y0)/(double)(*x1 - *x0); /* calculate the slope of the line */
tmp = (double)*x1 - (double)*x0;
if (tmp < (double)INT_MIN || tmp == 0.0 || tmp > (double)INT_MAX) {
return 0;
}
m = (*y1 - *y0)/tmp; /* calculate the slope of the line */
*y1 += (int)(m * (maxdim - *x1));
*x1 = maxdim;
return 1;
}
if (*x1 < 0) { /* other end is outside to the left */
m = (*y1 - *y0)/(double)(*x1 - *x0); /* calculate the slope of the line */
tmp = (double)*x1 - (double)*x0;
if (tmp < (double)INT_MIN || tmp == 0.0 || tmp > (double)INT_MAX) {
return 0;
}
m = (*y1 - *y0)/tmp; /* calculate the slope of the line */
*y1 -= (int)(m * *x1);
*x1 = 0;
return 1;
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